Microscope filter system



wwul VII E. S. BISSELL MICROSCOPE FILTER SYSTEM Filed March 27, 1935 Julie 15, 1937.

EVERETT S. BISSELL INVENTOR ATTORNEY UNITED STATES Otiill (ill HUD PATENT OFFICE MICROSCOPE FILTER SYSTEM Everett 8. Bissell, Irondequoit, N. Y., assignor to Bausch & Lomb Optical Company, Rochester, N. Y., a corporation of New York Application March 27, 1935, Serial No. 13,312

filters and more particularly to color filters for so-called "optical staining.

In the microscopic examination of some substances such as nearly transparent organisms, it is frequently necessary to stain the specimens with some form of dye before they can be readily seen and studied. This presents a disadvantage in that the dye frequently kills or injures the 0 organism. The Rheinberg filter was designed to overcome this difiiculty by optically staining the specimens. The Rheinberg filter is one using both bright and dark field illumination where the two illuminating beams are of contrasting colors so that the organism stands out against a field of contrasting color.

One of the objects of the present invention is to provide a new and improved form of microscope filter which is simple and inexpensive to 0 manufacture yet. efficient in operation. A further object is to provide a filter for optically staining specimens and which can be substituted for the conventional dark ground stop. These and other objects and advantages reside in cer- 25 tain novel features of construction, arrangement and combination of parts as will hereinafter be more fully set forth and pointed out in the appended claims.

Referring to the drawing:

Fig. 1 is a vertical section of a microscope condensing system showing an embodiment of my invention.

Fig. 21s a top plan view of the filter holder.

A preferred embodiment of my invention is 35 illustrated in the drawing wherein ill indicates generally a microscope condenser mount holding lenses H and i 2 for directing light through the slide l3 and cover glass ll to the objective-l5. Beneath the lens II the condenser mount l0 carries the usual diaphragm l6 and also the usual support l1 for a filter or dark field stop.

The filter support made according to the present invention comprises a large annular member l8 and a smaller annular member I! held in substantially concentric relation to the large annular member i8 by arms 20. A flange II is formed on the outer edge of the member II and a flange 22 is formed on the outer edge of the member l9 thus forming two shallow concentric cups. This support can be readily and inexpensively stamped from a single piece of metal.

An annular color filter 23 is placed in the space between the fiangm 2i and 22 and a small circular filter 2!, usually of contrasting color, is placed within the flange 22. As can be seen from Fig. l, the light passing through the filter 23 strikes the specimen at too great an angle to enter the objective I! while that passing through the filter 24 enters the objective it directly. In this way the specimen is illuminated by a colored beam which does not directly enter the condenser and appears against a field of contrasting color. The filter elements 23 and 24 canbe of celluloid, glass or other suitable substance.

From the foregoing it is apparent that I am able to attain the objects of my invention and provide a new and improved microscope filter which is simple and inexpensive to manufacture yet efiicient in operation. The filter support would be supplied with a variety of annular filter elements 23 and a variety of filter elements 24 so that the colors can be changed at will and different combinations could be used to provide any desired contrast. An opaque stop can obviously be substituted for the filter element 24.

Various modifications can, of course, be made without departing from the spirit of my invention.

I claim:

1. A rigid filter support comprising two shallow annular members of different size, and an arm for holding said members in substantially concentric relation, an annular filter adapted to rest on said arm and to extend between. said members and a second filter adapted to lie within and rest upon the inner member.

2. A microscope filter for optically staining specimens comprising an annular member, an inwardly extending arm secured to said member, a second annular member carried by said arm substantially concentric with said first member, an upturned fiange on the outer edge of said second member, an annular filter adapted to surround said fiange and a second filter adapted to lie within said flange.

3. A microscope filter for optically staining specimens comprising an annular member having an upturned flange on its outer edge, an inwardly extending arm secured to said member, a second annular member substantially concentric with said first member secured to said arm, said second annular member having an upturned fiangeon its outer edge, an annular color filter between said two flanges and a second color filter within the flange of said second annular member.

S. BISSELL. 

